It is retrospective patient chart study among psychiatrists and primary care physicians (PCPs) treating patients suffering from major depressive disorder (MDD). Physicians will be asked general medical questions in order to quantify their prescribing behavior and their perception of treatment performance. A retrospective patient chart review will then be performed and patient data will be collected to document patient characteristics and actual treatment outcomes. Upon qualification, specific instructions for chart review will be provided. Once the identified charts are pulled, the physicians are instructed to continue with the on-line survey. In total, there will be approximately 450 psychiatrists and 450 primary care physicians participating in this trial.